This disclosure relates to door hinges. More particularly, it relates to a hinge pin for a door hinge assembly, wherein the hinge pin includes a channel for the introduction of a lubricant from the head of the hinge pin into the narrow spaces between the bearing surfaces of the hinge plate knuckles that rotate around the hinge pin shaft.
Conventional door hinge assemblies, as disclosed, for example, in U.S. Pat. No. 8,191,205, include a first hinge plate with an inner edge and a second hinge plate having an inner edge adjacent the inner edge of the first plate. A first set of hollow tubular knuckles extends from the inner edge of the first plate, and a second set of hollow tubular knuckles extends from the inner edge of the second plate. The respective knuckles of the first and second sets of knuckles are interdigitated so that they are aligned along a pivot axis to form a continuous passageway configured to receive the shaft of a hinge pin that pivotably joins the hinge plates to each other along the pivot axis. When thus joined, the hinge plates are rotatable about the axis defined by the hinge pin shaft.
In the typical door hinge assembly, as described above, the hinge pin shaft is usually lubricated on assembly. Because the clearance between the interdigitated knuckles may be quite tight, however, little of the lubricant may actually migrate to the metal-on-metal bearing surfaces between adjacent knuckles. Thus, over time, the hinge may begin to squeak when the door is opened and closed. Curing this problem usually necessitates the removal of pin from the hinge assembly, which often requires the removal of the door as well. Accordingly, a hinge assembly construction has been sought that provides for lubrication of these bearing surfaces without the need for any disassembly.